JPH0320502Y2 - - Google Patents

Description

[Detailed Description of the Invention] Technical Field The present invention relates to a multi-cylinder internal combustion engine equipped with an intake port equipped with a valve for generating drift.

Prior Art A valve for generating a biased flow is rotatably provided in the intake port of an internal combustion engine, and when the engine is operated at a partial load, the valve for generating a biased flow causes a bias in the intake air-fuel mixture in the intake port, thereby causing a flow inside the combustion chamber. An internal combustion engine is known that improves combustion by creating a swirling flow in the intake air-fuel mixture (Japanese Patent Laid-Open No. 1986-
128418).

In a multi-cylinder internal combustion engine, each intake port is provided with a valve for generating a biased flow, but it is difficult to make the opening areas of these valves match each other, so the intake air-fuel mixture amount and the strength of the swirl flow are It is different for each cylinder, and there is a possibility that the combustion state will be different for each cylinder. For this reason, in multi-cylinder internal combustion engines, it has been difficult to put into practical use an intake port equipped with a valve for generating a biased flow.

Purpose of the invention The purpose of this invention is to put into practical use an intake port equipped with a valve for generating a biased flow in a multi-cylinder internal combustion engine. resolved,
It is an object of the present invention to provide a multi-cylinder internal combustion engine that can balance combustion conditions between cylinders.

Structure of the Device In order to achieve the above object, the present invention provides a compensation port for compensating for the imbalance in the flow rate of the mixture downstream of the valve for generating a biased flow, and also connects the compensation port of each intake port with a communicating pipe. By communicating with each other, the air-fuel mixture from other intake ports that are not in the intake stroke is ejected from the compensation port to the intake port in the intake stroke according to the opening area of the valve for generating drift, and as a result, each intake port is in the intake stroke. This is intended to compensate for the imbalance in the intake air-fuel mixture flow rate between ports.

However, in this case, the compensation port must be provided at a position where the strength of the uneven flow and the flow velocity distribution are not deteriorated by the air-fuel mixture jetted out from the compensation port.

For this reason, the present invention further provides that the compensation port is disposed at a distance within 1/4 of the intake port width from the intake port wall surface where the biased flow exists, and
The cylinder is characterized by being arranged so that its axis includes the center axis of the intake port and is parallel to a plane parallel to the cylinder center axis.

Embodiments Next, embodiments of the present invention will be described with reference to the accompanying drawings.

Fig. 1 is a conceptual plan view of a four-cylinder internal combustion engine embodying the present invention, Fig. 2a is a schematic enlarged horizontal cross-sectional view of an arbitrary cylinder of the engine shown in Fig. It is a sectional view taken along arrow A. In these figures, 10
12 is a cylinder head, 12 is a cylinder bore, 14 is a combustion chamber, 16 is an exhaust port that guides combustion gas from the combustion chamber to the outside, and 18 is an intake port that introduces a mixture of fuel and air into the combustion chamber.

Inside each intake port 18, a butterfly-shaped valve 20 for generating biased flow is rotatably provided. These valves 20 are connected to an actuator (not shown) by a valve driving device disclosed in, for example, Japanese Patent Application No. 58-41517, and are closed (position shown) when the engine is under partial load. The valve opens according to the increase. The rotation axis 22 of each valve 20 is offset in the direction of the intake port inner wall surface 26 with respect to the central axis 24 of the intake port 18, and a narrow gap 30 is formed between the valve 20 and the intake port outer wall surface 28. .

In accordance with the present invention, a compensating port 32 is provided in the wall of each intake port 18 downstream of the valve 20. Each compensation port 32 is communicated with each other by a communication pipe 34. A capacity space 36 is formed in the communication pipe 34 to reduce pressure pulsations within the communication pipe 34. Communication pipe 34
The shape, volume, and cross-sectional shape of each part of the capacity space 36 must be sufficient to compensate for the imbalance in the air-fuel mixture flow rates between the intake ports.

The position of the compensation port 32 is determined within about 1/4 of the intake port width from the intake port wall surface where drifting occurs, that is, the intake port outer wall surface 28. Further, the direction of the compensation port 32 is such that its axis is parallel to a plane that includes the intake port center axis 24 and is parallel to the cylinder center axis 0.

Next, the operation of the compensation port will be explained with reference to FIG. When the engine is under partial load, the drift valve is closed as shown in FIG.
During the intake stroke, the air-fuel mixture passes through the gap 30 and flows only along the outer wall surface 28 of the intake port and enters the combustion chamber, forming a swirling flow. At the same time, due to the negative pressure generated downstream of the bias flow generating valve 20,
The air-fuel mixture is injected from the intake ports of other cylinders that are not in the intake stroke through the communication pipe 34 to the intake ports that are in the intake stroke. The flow rate of this air-fuel mixture ejected from the compensation port 32 increases in accordance with the strength of the negative pressure downstream of the drift-generating valve, so the intake air-fuel mixture flow rate due to the mismatch in the opening area of the drift-generating valve between cylinders is reduced. Imbalance among the cylinders can be compensated for, the air-fuel mixture can be evenly distributed to each cylinder, and the strength of the swirling flow can be made uniform.

During high-load operation, the valve for generating a biased flow is opened. In this case, the drift in the intake port disappears and the swirling flow weakens, but the intake resistance decreases and the air-fuel mixture filling efficiency increases, resulting in high output.

Next, consider the position and direction of the compensation port. If the position of the compensation port 32 is moved to the left in the figure at right angles to the intake port center axis 24 in FIG. As a result, the biased flow in the intake port is substantially eliminated and the swirling flow in the combustion chamber is attenuated, thereby reducing the combustion improvement effect obtained. That is, when the compensation port is provided on the intake port inner wall surface 26 as shown in FIG. 4a, for example, the air-fuel mixture ejected from the compensation port also flows near the center of the intake port as shown by the arrow. On the other hand, when the air-fuel mixture is provided on the outer wall surface 28 of the intake port as shown in FIG. be.

As a result of studies conducted by the inventor of the present invention, it was found that if the compensating port 32 is located at a distance within 1/4 of the intake port width from the outer wall surface 28 of the intake port, the biased flow necessary for forming a swirling flow can be achieved. It turned out that it was possible. That is, if provided at this position, the air mixture flow from the compensation port will flow along the intake port outer wall surface 28 as shown in FIG. 3, and will not prevent the formation of a biased flow. Further, the direction of the axis of the compensation port 32 is required to be parallel to a plane that includes the center axis 24 of the intake port 18 and is parallel to the cylinder center axis 0, as shown in FIG. If the axial direction of the compensation port 32 does not satisfy this condition, the air-fuel mixture ejected from the compensation port 32 will flow to the intake port 1.
8 or near the inner wall surface 26, the formation of polarized flow is prevented. Note that the compensation port 32 does not need to be formed perpendicularly to the wall surface of the intake port 18, and may be formed inclined toward the downstream side of the intake flow as shown by the broken line 32' in FIG. 2b. Often, such embodiments are also included.

Effects of the Invention As described above, the present invention provides a multi-cylinder internal combustion engine equipped with an intake port equipped with a valve for generating uneven flow. In addition, the compensation ports of each cylinder are communicated with each other through a communication pipe, so that the air-fuel mixture is distributed uniformly to each cylinder, and a uniform swirling flow is formed in each cylinder. Combustion conditions are equalized. Furthermore, the compensation port is provided close to the outer wall surface of the intake port, and its axis includes the center axis of the intake port and is parallel to a plane parallel to the cylinder center axis. The air-fuel mixture is ejected along the polarized flow, so it does not interfere with the polarized flow and attenuate the swirling flow.

[Brief explanation of the drawing]

Fig. 1 is a conceptual plan view of a multi-cylinder internal combustion engine of the present invention, Fig. 2a is a schematic enlarged horizontal sectional view of an arbitrary cylinder of the engine of Fig. Fig. 3a is a cross-sectional view similar to Fig. 2a, illustrating the state of formation of drifting, Fig. 3b is a sectional view taken along arrow A in Fig. 3a, and Figs. 4a and b are cross-sectional views. FIG. 6 is a reference diagram for comparing the position of a compensation port and the state of formation of a biased flow. 10... Cylinder head, 12... Cylinder bore, 14... Combustion chamber, 18... Intake port, 20
... Valve for generating biased flow, 24 ... Intake port center axis, 26 ... Inner wall surface of intake port, 28 ... Outer wall surface of intake port, 30 ... Gap, 32 ... Compensation port, 34 ... Communication pipe , 38...A plane including the cylinder center axis.

Claims (1)

[Scope of Claim for Utility Model Registration] A valve for generating a biased flow is provided in each intake port of a multi-cylinder internal combustion engine so as to be rotatable around a rotating shaft extending in the vertical direction of the cylinders. In a multi-cylinder internal combustion engine that generates a drift in the air-fuel mixture, thereby creating a swirling flow in the air-fuel mixture in the combustion chamber, each intake port wall has an imbalance in the flow rate of the air-fuel mixture downstream of the valve for creating the drift. A compensation port is bored and opened to the intake port, and the compensation ports of each cylinder are communicated with each other through a communication pipe, and the compensation port is connected to the intake port width dimension from the intake port wall surface where uneven flow exists. A multi-cylinder internal combustion engine, characterized in that the engines are arranged at a distance within 1/4 of each other, and their axes are parallel to a plane that includes the center axis of the intake port and is parallel to the cylinder center axis. .